A Critical Comparison: Copper, Silver, and Gold

Hashmi, A. Stephen K.

doi:10.1002/9780470597521.ch12

Cited by 43 publications

(31 citation statements)

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“…of the corresponding tetrabutylammonium halide was added to the tube (0.1 ml, 0.168 M). Final concentrations: [1 ClO4 ] ¼ 12 mM and [nBu 4 NX] ¼ 24 mM (X ¼ Cl, Br, I). Upon addition of the halides, the solution rapidly turns deep orange, indicating some degree of deprotonation of the complex.…”

Section: Methodsmentioning

confidence: 99%

“…It is generally accepted that silver involves exclusively oneelectron redox chemistry 4,[14][15][16][17] , in contrast to the other two group-11 metals, copper and gold, which can undergo twoelectron redox chemistry. Copper and gold have been directly implicated in M(I)/M(III) oxidative addition and reductive elimination processes [18][19][20][21][22][23][24][25] , whereas such chemistry has never been considered for silver.…”

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confidence: 99%

“…Silver holds the most unexplored chemistry among the coinage metals and its redox chemistry is the least understood [1][2][3][4][5] . Ag(I) salts are commonly employed in organic transformations by exploiting three main properties (Fig.…”

mentioning

confidence: 99%

“…1). First, its moderate Lewis acidity has found application in activating allenes and alkynes to promote a nucleophilic attack over the unsaturation to render, for instance, the cyclization of allenols, allenones and allenoic acids 4,5 . The p-activation of terminal acetylenes can also produce silver(I)-acetylides 6,7 , which are known as efficient transmetallating agents and have been widely utilized in organopalladium catalysis [8][9][10] .…”

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Direct observation of two-electron Ag(I)/Ag(III) redox cycles in coupling catalysis

et al. 2014

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Silver is extensively used in homogeneous catalysis for organic synthesis owing to its Lewis acidity, and as a powerful one-electron oxidant. However, two-electron redox catalytic cycles, which are most common in noble metal organometallic reactivity, have never been considered. Here we show that a Ag(I)/Ag(III) catalytic cycle is operative in model C–O and C–C cross-coupling reactions. An aryl-Ag(III) species is unequivocally identified as an intermediate in the catalytic cycle and we provide direct evidence of aryl halide oxidative addition and C–N, C–O, C–S, C–C and C–halide bond-forming reductive elimination steps at monometallic silver centres. We anticipate our study as the starting point for expanding Ag(I)/ Ag(III) redox chemistry into new methodologies for organic synthesis, resembling well-known copper or palladium cross-coupling catalysis. Furthermore, findings described herein provide unique fundamental mechanistic understanding on Ag-catalysed cross-coupling reactions and dismiss the generally accepted conception that silver redox chemistry can only arise from one-electron processesThis work was supported by grants from the European Research Council (Starting Grant Project ERC-2011-StG-277801), the Spanish MINECO (CTQ2012-37420-C02-01/BQU, CTQ2012-32436, Consolider-Ingenio CSD2010-00065, INNPLANTA project INP-2011-0059-PCT-420000-ACT1) and the Catalan DIUE of the Generalitat de Catalunya (2009SGR637

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Direct observation of two-electron Ag(I)/Ag(III) redox cycles in coupling catalysis

et al. 2014

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“…However, the utility of pincerlike cyclic systems is not confined to copper chemistry, and recently studies with other group 11 metals as silver have emerged. In fact, silver holds the most unexplored chemistry among the coinage metals, and its redox chemistry is the least understood [68][69][70][71][72]. Silver redox chemistry is generally thought to stem exclusively from one-electron redox reactivity, in contrast to the two other coinage metals, copper and gold, which are known to undergo two-electron redox chemistry [73,74].…”

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confidence: 97%

Pincerlike Cyclic Systems for Unraveling Fundamental Coinage Metal Redox Processes

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Ribas

2015

The Privileged Pincer-Metal Platform: Coordination Chemistry &Amp; Applications

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Pincerlike cyclic ligands have overcome the high instability of transition metals in their higher oxidation states and have permitted the isolation of such species and the exhaustive study of their properties and reactivity. The formation and isolation of organometallic Cu II and M III (M¼Cu, Ag, Au) complexes stabilized by NCPs, carbaporphyrins, carbaporphyrinoids, heterocalixarenes, and triaza macrocyclic ligands will be discussed in this chapter. The study of these complexes have led to the discovery of unprecedented reactivity and proved the plausibility of often invoked pathways in copper-catalyzed cross-coupling reactions. Aryl-M III (M¼Cu, Ag) stable species have been implicated as the key intermediate species that operate in coupling catalysis through two-electron redox cycles involving oxidative addition and reductive elimination fundamental steps.

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Introduction to Silver Chemistry

Sivaguru

2018

Silver Catalysis in Organic Synthesis

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A Critical Comparison: Copper, Silver, and Gold

Cited by 43 publications

References 103 publications

Direct observation of two-electron Ag(I)/Ag(III) redox cycles in coupling catalysis

Direct observation of two-electron Ag(I)/Ag(III) redox cycles in coupling catalysis

Pincerlike Cyclic Systems for Unraveling Fundamental Coinage Metal Redox Processes

Introduction to Silver Chemistry

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